System for measuring smoke absorption into food products and method of making the system

ABSTRACT

A system for measuring smoke absorption into food products includes a surrogate that reacts to a presence of smoke in air ambient to the surrogate and the food products; and the surrogate is configured to change a state to a preselected degree after an exposure to the smoke for a time sufficient to effect a predetermined amount of smoke absorption by a selected food product. A method of making the system for measuring smoke absorption into food products includes placing the surrogate in air ambient to the surrogate in a smokehouse where the food products are to be smoked, configuring the surrogate to change a state after an exposure to the smoke for a time sufficient to effect a predetermined amount of smoke absorption by the food products; and measuring the change of state of the surrogate.

TECHNICAL FIELD

This disclosure relates to food preparation systems and processes, andmore particularly, to systems and processes for imparting a smoke flavorto food products.

BACKGROUND

A goal of commercial food preparation systems and processes is toproduce a food product that is consistently of high quality in a minimalamount of preparation time. Such systems and processes must produce highquality food products whose taste, texture, and appearance consistentlyfalls within a desired range, and which minimizes rejects. Achievingsuch consistency in commercial food product preparation is particularlydifficult when smoking food products. This is particularly difficultwhen smoking animal protein, because the rate of smoke absorption varieswith the type and cut of animal protein.

With most smoking processes, the food product to be smoked is placed inan enclosed chamber called a smokehouse. The food product may be placedon racks or hangers within the smokehouse, or pass through thesmokehouse on a conveyor. The air in the smokehouse is charged withsmoke from a smoke generator. The smoke generator may generate smoke bysmoldering or burning wood, which may be selected from hickory,mesquite, cherry, beech wood, pecan wood, apple wood, and oak.

The smoke generator may be located outside the smokehouse, in which casethe generated smoke is blown into the smokehouse through a duct. Inother designs, the smoke generator may be integrated with thesmokehouse. Most smokehouses also include an exhaust vent that may bepowered and operate together with the smoke generator to regulate thesmoke density in the air within the smokehouse. Smokehouses also mayinclude a regulated heating system to maintain the temperature withinthe smokehouse within a desired range, and a humidifier to regulatehumidity.

Factors including smoke density, temperature, food product residencetime within the smokehouse, the type of food product being smoked, andthe desired level of smoke absorption must be controlled to produce thedesired level of smoke flavor in the food product. Typically, thesefactors are controlled by an experienced operator who relies on theirskill at setting these operating parameters of the smokehouse. Suchsubjective setting and control can lead to inconsistent levels of smokeflavor absorbed by the food product between batches or runs, and betweenfood product smokehouse facilities.

Attempts have been made to provide smokehouse operation that utilizesobjective measurement techniques. In one example, sample smoke productsare ground to make a slurry and their pH is measured to determinewhether a desired level of smoke is absorbed by the smoked food product.Because smoke is acidic, an increase in the pH of a food product isindicative of an amount of smoke absorbed. A disadvantage with such aprocess is that it requires the continual destruction of the selectedfood product being smoked to monitor the progression of smokeabsorption, and to determine when a desired amount of smoke absorptionby the food product has occurred. This destructive testing creates foodproduct waste that adds to the production cost of the smoking operation.Further, if the tested food product indicates that too much smoke hasbeen absorbed by a batch or a run, the remaining food product of the runmust be degraded as second-rate product or rejected as waste.

Accordingly, there is a need for a system and method for measuring smokeabsorption into food products that does not require destructive testingof the food products, and that relies on objective measurements topromote consistency. There is also a need for a system and method formeasuring smoke absorption into food products that operates and can bemonitored in real time during the smoking operation, thereby optimizingthe time required to achieve a desired amount of smoke absorption intothe food product.

SUMMARY

The present disclosure is a system and method for measuring smokeabsorption into a food product, and a method for making the system. Thesystem and method provide an objective determination of smoke absorptioninto a food product, thereby providing consistency and uniformity to thesmoked food product produced, without testing the food product itself.In exemplary embodiments, the disclosed system and method for measuringsmoke absorption determines the amount of smoke absorbed into a foodproduct in real time, which minimizes the likelihood of downgraded orrejected products due either to inadequate or excessive smokeabsorption.

In an exemplary embodiment, a system for measuring smoke absorption intofood products includes a proxy or surrogate that reacts to a presence ofsmoke in air ambient to the surrogate. The surrogate is configured tochange a state thereof to a preselected degree after an exposure to thesmoke for a time sufficient to effect a predetermined amount of smokeabsorption by a selected food product exposed to the smoke in the airambient to the surrogate.

In another exemplary embodiment, a system for measuring smoke absorptioninto food products includes a proxy or surrogate that reacts to apresence of smoke in air ambient to the surrogate and to the foodproducts, the surrogate including a casing made of a semipermeablemembrane and containing water; a conductivity meter having a probepositioned in the water within the casing to measure electricalconductivity of the water, wherein the electrical conductivity of thewater in the casing increases as the smoke in the air ambient to thesurrogate is absorbed through the semipermeable membrane and diffuses inthe water, and as the smoke in the air ambient to the surrogate isabsorbed into the food products; and a control that generates a signaland/or a display indicative of a selected electrical conductivity of thewater that corresponds to a selected amount of smoke absorption by thefood products exposed to the smoke in the air ambient to the surrogate.

In yet another exemplary embodiment, a method of making a system formeasuring smoke absorption into food products includes placing a proxyor surrogate that reacts to a presence of smoke in air ambient to thesurrogate in a smokehouse where the food products are to be smoked, thesurrogate is configured to change a state thereof to a preselecteddegree after an exposure to the smoke for a time sufficient to effect apredetermined amount of smoke absorption by a selected food productexposed to the smoke in the air ambient to the surrogate; and placing aprobe of a sensor in the surrogate to measure a degree of the change ofstate of the surrogate, the sensor calibrated to indicate a selecteddegree of the change of state corresponding to a selected amount ofsmoke to be absorbed by the food products.

In still another exemplary embodiment, a method for measuring smokeabsorption into food products includes placing a proxy or surrogate thatreacts to a presence of smoke in air ambient to the surrogate in apresence of the food products; detecting a predetermined degree ofchange in a state of the surrogate after an exposure to the smoke for atime sufficient to effect a predetermined amount of absorption of thesmoke by the food products exposed to the smoke in the air ambient tothe surrogate; and removing the smoke in air ambient to the foodproducts to end the smoke absorption.

Other objects and advantages of the disclosed system for measuring smokeabsorption into food products and method of making the system will beapparent from the following description, the accompanying drawings, andthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation of a smokehouse incorporating anexemplary embodiment of the disclosed system for measuring smokeabsorption into food products;

FIG. 2 is a schematic top plan view of another exemplary embodiment ofthe disclosed system for measuring smoke absorption into food products;

FIG. 3 is a flow chart showing an exemplary embodiment of the method formaking the disclosed system for measuring smoke absorption into foodproducts;

FIG. 4 is a flow chart showing an exemplary embodiment of the method forusing the disclosed system for measuring smoke absorption into foodproducts; and

FIG. 5 is a schematic side elevation of a smokehouse incorporatinganother exemplary embodiment of the disclosed system for measuring smokeabsorption into food products.

DETAILED DESCRIPTION

In an exemplary embodiment, the disclosed system for measuring theamount of smoke absorbed into a food product. As used herein the term“food product” or “food products” includes any food or food ingredientfor human consumption, and includes meats, in particular pork bellies,fish, cheeses, sausages and other prepared meats, spices, vegetables, inparticular root vegetables, fruits, nuts, and food ingredients. Thedisclosed system utilizes a surrogate, which is not itself the foodproduct, nor is it derived from or taken from the food product that issmoked. Instead, the surrogate consists of or contains a substance thatreacts to the chemical properties of smoke.

Smoke is mixture of different compounds dissolved or carried in air. Ithas been determined that acidic compounds make up approximately 96% ofthe smoke composition. Without being held to any particular theory, itis generally accepted that smoke is absorbed into a food product, suchas a protein, by dissolving itself in water contained in the protein. Asthe protein cooks, the moisture is driven off, leaving the smokecompounds behind that are responsible for flavor and color changes tothe food product.

Accordingly, in an exemplary embodiment described herein, the systemutilizes a proxy or surrogate, such as water, in particular distilled ordeionized water, as a suitable substitute or proxy to determine theamount of smoke absorbed into a food product, such as a moisture-ladenprotein, in particular a pork belly, while in a smokehouse. During thesmoking process, the surrogate is tested to determine the rate of smokeabsorption by the surrogate, which is indicative of the rate of smokeabsorption into the food product.

The relation between the rate of smoke absorption into the surrogate andthe rate of smoke absorption into the food product is determinedempirically. A change of the state of the surrogate to a preselecteddegree caused by absorption of smoke into the surrogate, which may takethe form of a change in pH of the water in the surrogate to apreselected degree, such as a preselected level of acidity and/or achange in electrical conductivity of the water in the surrogate to apreselected degree, such as a preselected conductivity, is measuredcontinuously during the smoking process. When the target pH and/orconductivity of the water in the surrogate is reached, the smokingprocess is completed for the food products in the smokehouse.

As shown in FIG. 1, an exemplary embodiment of the system for measuringsmoke absorption into food products, generally designated 10, is usedwith, or incorporated into, a smokehouse, generally designated 12. Thesmokehouse 12 typically is an enclosed room 14 with a top wall 16, fourside walls 18, and a floor 20 defining an interior 22. One of the sidewalls 18, or an access door 19 in the wall, includes an inspectionwindow 24 that allows an operator to view the interior 22. The accessdoor 19 (there may be two or more, but only one is shown) enables anoperator to enter to load and remove food products to be smoked. In anexemplary embodiment, the smokehouse 12 includes a conveyor 26 thatpasses through openings 28, 30 in the walls 18.

As an alternative to the conveyor 26, or in addition to the conveyor,the smokehouse 12 includes a rack system 32 for hanging food product 34Ain the interior. The conveyor 26 includes a belt 36 that supports foodproduct 34B and conveys it through the interior 22. The smokehouse 12includes a smoke generator 38 that is connected to the interior 22 by aconduit 40 and includes a smoke generator fan 39 for blowing or drawingsmoke into the interior 22 of the smokehouse 12. In embodiments, theenclosed room 14 includes an intake vent 41 that may include an intakefan, combined with an exhaust vent 42 that may include an exhaust fan.

The smokehouse 12 may include a humidification valve 43 that allowssteam and/or water mist into the interior 22 to regulate the humidity ofthe interior. The intake and exhaust vents 41, 42, respectively, areactuated in cooperation with the smoke generator 38 and smoke generatorfan 39 to control the density of smoke in the interior 22. In exemplaryembodiments, the smoke generator 38 generates smoke by burning orsmoldering a selected combustible material, such as wood, for examplehickory, mesquite, apple wood, oak, cherry, beech wood, pecan wood,and/or ash. The wood itself may be flavored with spices, essential oils,herbs, or spirits, such as bourbon.

The smoke generator fan 39 can be set to blow smoke into the interior 22of the room 14 at selected flow rates, and the intake vent 41 and/orexhaust vent 42 can be adjusted to vary flow rates as well. Thesmokehouse 12 also may include a heater 44 for heating the interior.Both the fan powering the exhaust vent 42 and the heater 44 may beadjusted to vary the exhaust flow rate and the rate of heat input to theinterior 22, respectively. The fan of the intake vent 41 is actuated todraw fresh air ambient to the exterior of the smokehouse, and the smokegenerator fan 39 draws or blows smoke into the smokehouse 12. Inembodiments, the smokehouse 12 also includes a thermometer and/or athermostat, which may be incorporated into the heater 44, as well as ahumidity sensor that may be incorporated into the humidification valve43.

The system 10 includes a proxy or surrogate 46A that reacts to apresence of smoke 48 in air ambient to the surrogate, namely, in theinterior 22 of the smokehouse 12. The surrogate 46A changes state afteran exposure to the smoke 48 for a time sufficient to effect apredetermined amount of smoke absorption by a selected food product 34Aand/or 34B exposed to the smoke in the air ambient to the surrogate. Thesurrogate is not the food product 34A, 34B in the smokehouse 12, and isnot derived from the food product in the smokehouse. In embodiments, thesurrogate 46A is a liquid or a gel 52, and the change of state is achange in a state of the liquid or the gel. In an exemplary embodiment,the change in state is a change in electrical conductivity to apreselected degree of electrical conductivity of the liquid or gel 52.In another exemplary embodiment, the change in state of the surrogate46A is a change in pH of the liquid or the gel 52 to a preselected pHvalue.

In the embodiment shown in FIG. 1, the surrogate 46A is contained withina casing 50 made of a semi-permeable membrane that permits absorption ofsmoke 48 from ambient air in the interior 22 of the smokehouse Inembodiments, the semipermeable membrane casing 50 is made of materialselected from animal intestine, cellulose, collagen, fibrous cellulose,and a polymer, all of which are permeable to smoke particles and gases,but impermeable to the liquid or the gel contained in the semipermeablemembrane of the casing, except through evaporation of the liquid aswater vapor. In an exemplary embodiment, the casing 50 is cylindrical ortubular in shape and is tied or otherwise attached to and suspendeddownwardly from a bracket 54 that is mounted on a wall 18 of thesmokehouse 12.

In a particular embodiment, the surrogate 46A is contained within a4-foot length of casing 50 that is tied off at its opposing ends 56, 58and is suspended vertically within the interior 22. The casing 50contains the liquid 52 that is retained in its interior. In anembodiment, the liquid 52 is water, and in particular deionized ordistilled water. The system 10 also includes a sensor 60 that may takethe form of an electrical conductivity meter or a pH meter. The sensor60 includes, or is connected to receive a signal from, a probe 62 thatis mounted in the liquid 52 within the casing 50. In embodiments, theprobe 62 is connected by wire or wirelessly to communicate with thesensor 60.

In an exemplary embodiment, the system 10 includes a control 64, whichmay take the form of a programmable logic controller (PLC) or amicrocontroller. The control 64 is connected to receive a signal fromthe sensor 60 indicative of the electrical conductivity or the pH,respectively, of the liquid 52 of the surrogate 46A. The control 64 mayreceive a signal directly from the probe 62, by wire or wirelessly, ifthe sensor 60 is incorporated in the control. The control 64 isprogrammed to compare the conductivity or pH measured by the sensor 60and probe 62 to a selected or desired target conductivity or pH,respectively, for the selected food product 34A and/or 34B. Thisselected or desired conductivity or pH is developed by conducting testson various food products, in which a particular food product is testedusing varied settings of smoke density, temperature, and residence timewithin the interior 22 of the smokehouse 12.

The control 64 is connected to the smoke generator 38, and intake vent41 and exhaust vent 42 by cable 66, smoke generator fan 39 by cable 68,heater 44 by cable 70, humidification valve 43 by cable 71, and conveyor26 by cable 72. In embodiments, these communication and controlconnections are wired or wireless and/or part of a network, such as aneural network or a controller area network (CAN). In an embodiment, thesystem 10 includes a smoke detector 82, connected to the control 64wirelessly or by a cable 84, and may be part of a network. The smokedetector 82 measures the density of the smoke 48 in the interior 22. Thesmoke detector is mounted inside the enclosed room 14 of the smokehouse12 to sample the density of the smoke 48 in the interior 22. An exampleof a suitable smoke detector 82 is an MQ-2 gas sensor interfaced with anArduino board, which outputs a reading in parts per million of smoke inthe air that is conveyed to the control 64. The Arduino board may beseparate from or incorporated into the control 64. The control 64 isprogrammed to actuate the smoke generator 38 to maintain a selectedsmoke density in the interior 22.

In an exemplary embodiment, the control 64 is programmed to send anactuation signal to regulate the function of one or more of the smokegenerator 38, the fan of intake vent 41 and fan of exhaust vent 42,which may act in tandem, the heater 44, the smoke generator fan 39, andthe conveyor 26 in the smokehouse 12 containing the surrogate 46A andthe food products 34A and/or 34B to obtain the measured conductivity orpH in a selected range after a selected time interval of residence inthe smokehouse interior. In the case of the smoke generator 38, thecontrol 64 can actuate the smoke generator fan 39 to increase ordecrease the amount of smoke 48 generated and entering the interior 22and vary the flow rate of the intake vent 41 and/or exhaust vent 42 fan.With the heater 44, the control 64 can increase or decrease the amountof heat generated and blown or radiated into the interior 22, and thecontrol can increase or decrease the speed of the conveyor 26, therebyincreasing or decreasing the residence time of the food products 34B inthe interior 22 and consequent exposure to smoke 48.

As shown in FIGS. 1 and 2, in another exemplary embodiment, the system10′ includes a proxy or surrogate 46B. The surrogate 46B is a disk 74,or multiple disks 74, of pH indicator applied to a substrate 76. Thedisks 74 may be in solid, liquid, or paste form. The disks 74 of pHindicator are covered by a smoke-permeable gel layer 78, which, in anexemplary embodiment is a whey protein gel layer. Also in embodiments,the pH indicator is phenolphthalein. The substrate 76 may be a polymer,such as nylon, glass, sized paper, cardstock, or a clear polymer, suchas polyethylene terephthalate, an acrylic, or a polycarbonate.

The surrogate 46B is attached to the inside of the inspection window 24of the smokehouse 12, by a releasable adhesive or suction cups (notshown) or hung from a hook, or placed in the interior 22 where the disks74 of pH indicators can be seen visually through the inspection window24 by an operator. The thickness of the gel layer 78 is selected topermit penetration of the smoke 48 to the disks 74 at a selected ratethat corresponds to a desired or a selected penetration rate of smokeinto the food product 34A, 34B. The pH indicators of the disks 74 reactwhen contacted with the acidic smoke that has penetrated the gel layer78 and change color. The color change is a change in state of thesurrogate 46B that indicates that a sufficient amount of smoke hasabsorbed into the food product 34A, 34B.

In another exemplary embodiment, shown in FIG. 1, the system 10 formeasuring smoke absorption into food products 34A, 34B includes asurrogate 46A, which is not the food product, that absorbs smoke 48 inair within the smokehouse 12 ambient to the surrogate and to the foodproducts and in response changes state. The surrogate 46A includes acasing 50 made of a semipermeable membrane. The casing 50 contains aliquid 52, which in embodiments is water, in particular distilled waterand/or deionized water. Distilled and/or deionized water is not only pHneutral, but has little or no electrical conductivity.

A sensor 60 in the form of an electrical conductivity meter has a probe62 that is positioned in the liquid 52 within the casing 50 to measureelectrical conductivity of the liquid. The electrical conductivity ofthe liquid 52 in the casing 50 increases as the smoke 48 in the airambient to the surrogate 46A penetrates the semipermeable membranecasing 50 and diffuses in the liquid 52, and as the smoke in the airambient to the surrogate is absorbed into the food products 34A, 34B.

The control 64 generates a signal, which may take the form of an audibleand/or visual alarm incorporated in the control, and/or a screen displayon a display 80, indicating that a selected level of electricalconductivity of the liquid 52 has been reached that corresponds to aselected or desired amount of smoke absorption by the food products 34A,34B exposed to the smoke 48 in the air ambient to the surrogate withinthe room 14 of the smokehouse 12. Alternatively, or in addition, thedisplay 80 can receive a signal from the control 64 to show a real timepH and/or conductivity number readout and/or a graph showing cumulativeabsorption of smoke by the surrogate 46A. In embodiments, the control 64includes a data store, which may be remote, to store all readings of thesensor, paired with a time stamp and stock keeping unit (SKU) of thefood products, smoke density read by smoke detector 82, and othervariables including smoke temperature, meat temperatures, wet bulb anddry bulb temperature, relative humidity, and food product residencetime, for later reference.

The control 64 is adapted or programmed to regulate the function of oneor more of the smoke generator 38 of the smokehouse 12 containing thesurrogate 46A and the food products 34A, 34B, the intake vent 41 andexhaust vent 42, the humidification valve 43, the smoke generator fan39, the conveyor 26, and the heater 44 and heater fan. In theembodiments disclosed herein, the food product 34A, 34B is selected frommeats, in particular pork bellies, fish, cheeses, sausages and otherprepared meats, spices, vegetables, in particular root vegetables,fruits, nuts, and food ingredients.

Another exemplary embodiment of the system, generally designated 10″, isshown in FIG. 5. The system 10″ for measuring smoke absorption into foodproducts 34A, 34B includes a proxy or surrogate 46C, which is not thefood product, that absorbs smoke 48 in air within the smokehouse 12ambient to the surrogate and to the food products and in responsechanges state. The surrogate 46C is contained within a casing, which inthis embodiment takes the form of an open container 50. In embodiments,the container 50 is impermeable, such as a metal, glass, or plasticbucket or shallow pan. The container 50 contains a liquid 52, which inembodiments is water, in particular distilled water and/or deionizedwater. Distilled and/or deionized water is not only pH neutral, but haslittle or no electrical conductivity.

In an exemplary embodiment, the container 50 is attached to, mounted on,or suspended downwardly from a bracket 54 that is mounted on the wall 18of the smokehouse 12. In other embodiments, the container 50 is attacheddirectly to the smokehouse 12, such as to one of the walls 18 thereof,or attached to suspended from the ceiling 16.

The sensor 60 in the form of an electrical conductivity meter has aprobe 62 that is positioned in the liquid 52 within the container 50 tomeasure electrical conductivity of the liquid. The electricalconductivity of the liquid 52 in the container 50 increases as the smoke48 in the air ambient to the surrogate 46C contacts the surface of theliquid 52 that at the open top of the container 50 and diffuses in theliquid, such as water, as the smoke in the air ambient to the surrogateis absorbed into the food products 34A, 34B.

The control 64 generates a signal, which may take the form of an audibleand/or visual alarm incorporated in the control, and/or a screen displayon a display 80, indicating that a selected level of electricalconductivity, or selected pH, of the liquid 52 in the container 50 hasbeen reached that corresponds to a selected or desired amount of smokeabsorption by the food products 34A, 34B also exposed to the smoke 48 inthe air ambient to the surrogate 46C within the room 14 of thesmokehouse 12.

Alternatively, or in addition, the display 80 receives a signal from thecontrol 64 to show a real time pH and/or conductivity number readoutand/or a graph showing cumulative absorption of smoke by the surrogate46C. In embodiments, the control 64 includes a data store, which may beremote, to store all readings of the sensor, paired with a time stampand SKU of the food products, smoke density read by smoke detector 82,and other variables including smoke temperature, meat temperatures, wetbulb and dry bulb temperature, relative humidity, and food productresidence time, for later reference.

The control 64 is adapted to regulate the function of one or more of thesmoke generator 38 of the smokehouse 12 containing the surrogate 46C andthe food products 34A, 34B, the intake vent 41 and exhaust vent 42, thehumidification valve 43, the smoke generator fan 39, the conveyor 26,and the heater 44 and heater fan. In the embodiments disclosed herein,the food product 34A, 34B is selected from meats, in particular porkbellies, fish, cheeses, sausages and other prepared meats, spices,vegetables, in particular root vegetables, fruits, nuts, and foodingredients.

As shown in FIG. 3, a method 100 of making the system 10, 10′, 10″ formeasuring smoke absorption into food products 34A, 34B begins withmaking the proxy or surrogate 46A, 46B, 46C as indicated by block 102.In the embodiment shown in FIG. 1, as indicated in block 104, making thesurrogate 46A includes taking a casing 50 made of a semipermeablemembrane, filling it with liquid or gel 52, placing a probe 62 in theliquid or gel within the casing, and in embodiments sealing the opposingends 56, 58 of the casing to retain the liquid or gel and probe therein.In other embodiments, the casing 50 is selected from an open containeror pan that may be plastic, glass, or metal. In embodiments, the liquid52 is used and is water, in particular distilled water or deionizedwater.

In the embodiment shown in FIG. 2, the surrogate 46B is made byattaching the disks 74, which may be of any shape in addition to round,of a pH indicator to a substrate 76, and covering the disks with thesmoke-permeable gel layer 78. In the embodiment shown in FIG. 5, thesurrogate 46C is made by placing the container 50 in the interior 22 ofthe smokehouse 12, filling the container with liquid or gel 52, andplacing the probe 62 in the liquid or gel.

As indicated in block 106, with the embodiments of 10, 10′, 10″ thesurrogate 46A, 46B, 46C, respectively, is placed in the interior 22 ofthe smokehouse 12, where it will be exposed to smoke 48 in air ambientto the surrogate where the food products 34A, 34B are to be smoked. Witheach embodiment of the system 10, 10′, 10″ the surrogate 46A, 46B, 46Cis configured to change its state after an exposure to the smoke 48 fora time sufficient to effect a predetermined amount of smoke absorptioninto the selected food product 34A, 34B exposed to the smoke in the airambient to the surrogate.

As indicated in block 108, before or after placing the probe 62 of thesensor 60 in the surrogate 46A, 46C to measure a degree of the change ofstate of the surrogate, the sensor is calibrated or programmed toindicate a selected degree of the change of state corresponding to aselected amount of smoke 48 to be absorbed by the food products 34A,34B. This calibration or programming utilizes data gathered empirically,recording smoke density, air temperatures, humidity, and residence timefor various types and forms of food products 34A, 34B from previouslyconducted smokehouse 12 operations.

As indicated in block 110, if the system 10 is used, then the sensor 60is connected to or incorporated in the control 64, and the control isconfigured to regulate the function of one or more of the smokegenerator 38, the smoke generator fan 29, the intake vent 41 and exhaustvent 42, the humidification valve 43, the conveyor 26, and the heater 44of the smokehouse 12. With the system of FIG. 1, as indicated in block106, the surrogate 46A is placed in the smokehouse 12, which includesplacing the casing 50 made of a semipermeable membrane in the smokehouseafter the casing has been filled with the surrogate in the form of aliquid or gel 52, preferably water, and placing the probe 62 in theliquid. Placing the probe 62 of the sensor 60 in the surrogate 46Aincludes placing the probe in the surrogate to measure the electricalconductivity or the pH of the liquid 52. With the system of FIG. 5, asindicated in block 106, the surrogate 46C is placed in the smokehouse12, which includes placing the container 50 in the smokehouse andfilling the container with the liquid 52, in particular distilled and/ordeionized water, and placing the probe 62 in the liquid. Placing theprobe 62 of the sensor 60 in the surrogate 46A, 46C includes placing theprobe in the surrogate to measure the electrical conductivity or the pHof the liquid or gel 52.

As shown in FIG. 4, a method for measuring smoke absorption into foodproducts, generally designated 200, begins by placing the proxy orsurrogate 46A, 46B, 46C that reacts to a presence of smoke 48 in airambient to the surrogate in the presence of the food products 34A, 34Bin the interior 22 of the smokehouse 12, as indicated in block 202. Withthe surrogate 46B of FIG. 2, the surrogate is mounted within theinterior 22 where it can be observed visually through the window 24. Thenext step is indicated by following dashed line from block 202 to block204. The food products 34A, 34B are placed or conveyed into the interior22 of the smokehouse 12, and the smoke generator 38 and smoke generatorfan 39 actuated to create and convey smoke 48 into the interior to beginthe smoking process. Temperature and humidity may be adjusted by thecontrol 64 actuating the heater 44 and/or humidification valve 43.

As the smoke 48 penetrates the gel layer 78 to the disks 74 of thesurrogate 46B, an operator detects a predetermined degree of change ofthe state of the disks 74 of the surrogate 46B after an exposure to thesmoke 48 for a time sufficient to effect a predetermined or desiredamount of smoke absorption into the food products 34A, 34B exposed tothe smoke in the air ambient to the surrogate in the smokehouse 12. Thechange of the state of the disks 74 may take the form of a change incolor of the disks.

As indicated in block 206, the process ends when the surrogate 46Bchanges state (i.e., changes color). Optionally, as indicated in block208, during the process one or more of the food product residence time,smoke density, humidity, and/or air temperature are adjusted toaccelerate the smoking process. After the process 200 is completed, thespent surrogate 46B is removed from the smokehouse 12 and replaced witha fresh surrogate 46B to begin the next process or batch. At this timethe control 64 shuts off the smoke generator and heater 44, and actuatesthe intake and exhaust vents 41, 42 to remove the smoke 48 in the airambient to the food products to end their smoke absorption.

With the embodiments of FIGS. 1 and 5, as indicated in block 210, theprobe 62 is placed in the liquid or gel 52 of the surrogate 46A, 46C.Then, as indicated in block 212, the surrogate 46A 46C, with the probe62, is placed in the smokehouse 12 with the food products 34A, 34B. Theprobe 62 is connected to the sensor 60, which may or may not be integralwith the control 64, as indicated in block 214. Alternately, thesurrogate 46A, 46C is first placed in the smokehouse 12, and the probe62 is placed in the liquid or gel 62.

As indicated in block 216, the sensor 60 and/or control 64 is calibratedto a specific one or kind or type of the food product 34A, 34B (whichmay be specific to the type of food product, its thickness, and cut).The calibration of block 216 may be performed at the beginning of theprocess, such as at the time of making the surrogate 46A, or theplacement of surrogate in the smokehouse 12 and running tests forsurrogate 46C. As indicated in block 218, the food products 34A, 34B areplaced in the smokehouse 12, which includes either hanging the foodproducts 34A on rack system 32 or placing them on the belt 36 of theconveyor 26 to be conveyed into the interior 22 of the smokehouse 12.

As indicated in block 220, the smoking process begins when the smokegenerator 38 is actuated, which may be effected manually orautomatically by the control 64. The control 64 monitors or detects theincrease in the pH or the electrical conductivity of the liquid or gel52 in the casing 50, which indicates a change of state of the surrogate46A, 46C in real time during the food product smoking process, shown inblock 204. as detected by sensor 60. If necessary, the control 64adjusts the temperature by actuating the heater 44, and adjusts thedensity of the smoke 48 by actuating the smoke generator 38, and/or theintake and exhaust vents 41, 42, respectively, and the humidity byactuating the humidification valve 43, as indicated in block 208.

As indicated in block 206, the process 200 ends when the desired pH ordegree of electrical conductivity of the liquid or gel 52 is detected bythe sensor 60, reading a signal from the probe 62 in the liquid or gel52 of the surrogate 46A, 46C. The desired change of the state of theliquid or gel 52 in the casing or container 50 is transmitted to thecontrol 64, which shuts down the smoke generator 38 and actuates theintake and exhaust vents 41, 42, respectively, to clear the interior 22of smoke 48 to end the smoking process. The food product 34A, havingabsorbed the desired amount of smoke, may then be removed from thesmokehouse 12. If the conveyor 26 is used, the conveyor is indexed tothe next array of food products 34B. The now-spent surrogate 46A, 46C(and in the case of the surrogate of FIG. 2, the spent surrogate 46B),is removed from the smokehouse 12 and replaced with a fresh surrogate ina similar manner.

At this time, if the system 10′, 10″ is operating in batch mode, thecontrol 64 shuts off the smoke generator and heater 44 and actuates theintake and exhaust vents 41, 42 to remove the smoke 48 in the airambient to the food products 34A in the enclosed room 14 of thesmokehouse 12 to end their smoke absorption. If the system 10′, 10″ isoperating in a continuous mode, the control 64 actuates the conveyor 26to move the food products 34B on the conveyor out of the enclosed room14 of the smokehouse 12 to end their smoke absorption.

The foregoing systems and methods provide objective, repeatable meansfor measuring smoke absorption into a wide array of food products.Moreover, the methods and systems are employed in real time, during thesmoking process, which minimizes the possibility of oversmoking orundersmoking the food products. This may result in a reduction in theamount of time a food product needs to remain in the smokehouse, and areduction in the amount of smoke needed to produce the desired color andflavor changes in the food product. Moreover, use of the disclosedsystems and methods over time would enable operators to determine theexact levels of desired smoking for many types of food products, andreducing waste due to quality downgrades.

While the forms of apparatus and methods described herein are preferredembodiments of the disclosed system and process for measuring smokeabsorption into food products, and method of making, it should beunderstood that the invention is not limited to these specific systemsand processes, and that changes may be made therein without departingfrom the scope of the invention.

What is claimed is:
 1. A system for measuring smoke absorption into foodproducts, the system comprising: a surrogate that reacts to a presenceof smoke in air ambient to the surrogate; and the surrogate isconfigured to change a state thereof to a preselected degree after anexposure to the smoke for a time sufficient to effect a predeterminedamount of absorption of the smoke by a selected food product exposed tothe smoke in the air ambient to the surrogate.
 2. The system of claim 1,wherein the surrogate is selected from a liquid and a gel layer, and thechange of the state is a change in the state of the liquid or the gellayer.
 3. The system of claim 2, wherein the change of the state is achange in electrical conductivity to a preselected degree of electricalconductivity.
 4. The system of claim 2, wherein the change of the stateis a change in pH to a preselected pH value.
 5. The system of claim 1,wherein the surrogate is a pH indicator applied to a substrate.
 6. Thesystem of claim 5, wherein the pH indicator is covered by a gel layer,in particular a whey protein gel layer.
 7. The system of claim 6,wherein the pH indicator is phenolphthalein.
 8. The system of claim 1,wherein the surrogate includes a liquid or a gel; and the system furthercomprises a probe that measures an electrical conductivity of the liquidor the gel, and an electrical conductivity meter or a pH meter,respectively, connected to the probe.
 9. The system of claim 8, furthercomprising a casing containing the surrogate, wherein the casing is madeof a semipermeable membrane that permits absorption of smoke fromambient air; and the probe is in the liquid or the gel and measures theelectrical conductivity of the liquid or the gel within the casing. 10.The system of claim 8, further comprising a container, and the containercontains the liquid or the gel; and the probe is in the liquid or thegel and measures the electrical conductivity of the liquid or the gelwithin the container.
 11. The system of claim 8, further comprising acontrol that is connected to receive a signal from the electricalconductivity meter or the pH meter indicative of the electricalconductivity or the pH, respectively, of the liquid or the gel.
 12. Thesystem of claim 11, wherein the control is programmed to compare themeasured conductivity or the measured pH to a selected conductivity orpH for the selected food product.
 13. The system of claim 11, whereinthe control is programmed to send an actuation signal to regulate afunction of one or more of a smoke generator, an intake fan, arecirculating fan, an exhaust vent, a heater, and a conveyor in asmokehouse containing the surrogate and the food products to obtain ameasured conductivity or pH in a selected range after a selected timeinterval.
 14. The system of claim 9, wherein the semipermeable membraneis selected from animal intestine, cellulose, collagen, fibrouscellulose, and a polymer.
 15. The system of claim 8, wherein the liquidis water.
 16. A system for measuring smoke absorption into foodproducts, the system comprising: a surrogate that reacts to a presenceof smoke in air ambient to the surrogate and to the food products; acasing made of a semipermeable membrane and containing water; a sensorselected from a conductivity meter and a pH meter, the sensor having aprobe positioned in the water within the casing to measure electricalconductivity of the water, wherein the electrical conductivity and thepH of the water in the casing increase as the smoke in the air ambientto the surrogate is absorbed through the semipermeable membrane anddiffuses in the water, and as the smoke in the air ambient to thesurrogate is absorbed into the food products; and a control thatgenerates a signal and/or a display indicative of a selected electricalconductivity of the water or a selected pH of the water that correspondsto a selected amount of smoke absorption by the food products exposed tothe smoke in the air ambient to the surrogate.
 17. The system of claim16, wherein the control is adapted to regulate a function of one or moreof a smoke generator of a smokehouse containing the surrogate and thefood products, an intake fan that draws smoke into the smokehouse, arecirculation fan that recirculates smoke-laden air within thesmokehouse, an exhaust vent of a smokehouse containing the surrogate andthe food products, a food products conveyor of a smokehouse containingthe surrogate and the food products, and a heater of a smokehousecontaining the surrogate and the food products.
 18. The system of claim16, wherein the food products are selected from meats, fish, cheeses,sausages, spices, vegetables, and fruits.
 19. A method of making asystem for measuring smoke absorption into food products, the methodcomprising: placing a surrogate that reacts to a presence of smoke inair ambient to the surrogate in a smokehouse where the food products areto be smoked, the surrogate is configured to change a state thereofafter an exposure to the smoke for a time sufficient to effect apredetermined amount of smoke absorption by a selected food productexposed to the smoke in the air ambient to the surrogate; and placing aprobe of a sensor in the surrogate to measure a degree of the change ofstate of the surrogate, the sensor calibrated to indicate a selecteddegree of the change of state corresponding to a selected amount ofsmoke to be absorbed by the food products.
 20. The method of claim 19,further comprising connecting the sensor to a control; and configuringthe control to regulate a function of one or more of a smoke generatorof a smokehouse containing the surrogate and the food products, anintake fan that draws smoke into the smokehouse, a recirculation fanthat recirculates smoke-laden air within the smokehouse, an exhaust ventof a smokehouse containing the surrogate and the food products, a foodproducts conveyor of a smokehouse containing the surrogate and the foodproducts, and a heater of a smokehouse containing the surrogate and thefood products.
 21. The method of claim 19, wherein placing the surrogatein a smokehouse includes placing a casing selected from a semipermeablemembrane and a container in the smokehouse, filling the casing with aliquid, preferably water, and placing the probe in the liquid.
 22. Themethod of claim 21, wherein placing a probe of a sensor in the surrogateincludes placing the probe of a sensor in the surrogate to measureconductivity or a pH of the liquid.
 23. A method for measuring smokeabsorption into food products, the method comprising: placing asurrogate that reacts to a presence of smoke in air ambient to thesurrogate in a presence of the food products; detecting a predetermineddegree of change in a state of the surrogate after an exposure to thesmoke for a time sufficient to effect a predetermined amount ofabsorption of the smoke by the food products exposed to the smoke in theair ambient to the surrogate; and removing the smoke in air ambient tothe food products to end the smoke absorption.